Information reproducing apparatus, data management information obtaining method, data management information obtaining program, and storage medium

ABSTRACT

An information reproducing apparatus reproducing information of an information recording medium is disclosed. In the information recording medium, a record area is divided into a plurality of data areas. Also, data are recorded for each of the divided data areas. In addition, management information relating to the data recording is recorded in a predetermined management information area. Further, the management information is updated and recorded in a new management information area every time a predetermined data recording is completed. A receiving part receives, from an external device, an obtaining request for the management information. The obtaining request includes designation of a specific management information area. A management information obtaining part obtains the management information relating to the data recording from the specific management information area designated in the received obtaining request. A reporting part reports, to the external device, the management information relating to the data recording obtained from the designated specific management information area.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention generally relates to informationreproducing apparatuses, data management information obtaining methods,data management information obtaining programs, and storage media thatreproduce data requested by users from recordable information recordingmedia such as DVD+Rs.

[0003] 2. Description of the Related Art

[0004] Recently, with the improvement of their functions, personalcomputers (PCs) have been able to handle AV (Audio-Visual) informationsuch as music and images. Since the amount of the AV information is veryhuge, optical discs such as CD-R (Compact Disc-Recordable) and DVD+R(Digital Versatile Disc+Recordable) have been attracting attention asinformation recording media. As the prices of the optical discs havebeen reduced, optical disc devices as information reproducingapparatuses have become widely used as one of the peripheral devices ofthe PCs.

[0005] There is the Universal Disc Format (UDF) standard as a filesystem using recordable information recording media such as CD-Rs andDVD+Rs. The UDF is the file system used for various devices andutilizing a record format that takes advantage of a characteristic ofeach device. Especially, CD-Rs and DVD+Rs apply the sequential UDF inwhich data are sequentially recorded from the inner side of a disc,since CD-Rs and DVD+Rs are write-once types that do not allowoverwriting of data.

[0006] Generally, in the sequential UDF, in order to maintain thecompatibility with ISO 9660, the first track is reserved and datarequested from a user are incrementally written from the second track.That is, the multi-track recording system that records data by dividinga session into a plurality of tracks, which form recording units, isused.

[0007] In the above-described recording state in the sequential UDF,since an unrecorded area exists in a session, reproduction is possibleonly by an information recording/reproducing apparatus, and it isimpossible to reproduce using an information reproducing apparatus suchas a CD-ROM drive or a DVD-ROM drive. However, when file systeminformation of record data is recorded to the first track (record fileinformation for achieving compatibility with ISO 9660), andlead-in/lead-out is recorded and closed, it is possible to reproduce thedata by a CD-ROM drive and a DVD-ROM drive. Further, CD-Rs, DVD+Rs andthe like use the multi-session recording system so as to further writeto such discs in which sessions are closed.

[0008] In the CD-R, the maximum track number is limited to 99 tracks,which is a small number. Thus, irrespective of the number of sessions,information of the tracks existing all over the disc is recorded in anarea called program memory area (PMA). Accordingly, it is possible tomanage the information of all the tracks. Hence, in a CD-R, it ispossible to immediately report the information of a track requested bythe user by storing, in the memory of a drive unit, the trackinformation obtained from the PMA.

[0009] On the other hand, the DVD+R allows recording of up to 191sessions in the record area. Each of the sessions allows recording of upto 16 tracks (referred to “fragments” in the DVD+R). That is, up to 3056(=191 ×16) fragments, which is a vast number, can exist on a DVD+R.Additionally, in the DVD+R, a lead-in of the second session (and latersessions) is called an “intro”, and a lead-out before the last sessionis called a “closure”. Information (fragment number, start address offragment, last address of fragment and the like, which are hereinafterreferred to as “fragment information”) relating to fragments in eachsession is recorded in a management information area called session disccontrol block (SDCB) that is recorded in the lead-in (or the intro) ofthe session. The SDCB includes information (session number, startaddress of session, last address of session and the like) relating toall sessions before the session as well as all fragment information ofthe session.

[0010] That is, in the DVD disc such as a DVD+R and DVD+RW, disc controlblocks (DCBs) indicating the record state of the disc exist, and a meansfor reporting DCB information to the user is prepared. In the DVD+R, asmentioned above, there are the DCBs such as the SDCBs that includeinformation of all sessions existing on the disc and information of allfragments existing in the session. In addition, in the DVD+RW, there isa formatting disc control block (FDCB) having information of the formatstate and the like. Since it is possible to overwrite the DVD+RW, whenthe format state is changed, the FDCB is overwritten and updated. On theother hand, since the DVD+R is a write-once. disc that cannot beoverwritten, the SDCB is updated and recorded in a predetermined newSDCB area every time a session or a fragment is added.

[0011] By the way, there is a case where an upper device (for example, aPC) using such an optical disc device requires, prior to reproducing anoptical disc, management information relating to data recorded on theoptical disc. Thus, the upper device is configured to be able torequest, from the optical disc device, the management information(number of sessions included in the record area and the like, which arehereinafter referred to as “session information”) relating to sessionsof the optical disc and information (number of tracks included in therecord area, track address indicating a track position, and the like,which are hereinafter referred to as “track information”) relating totracks.

[0012] Corresponding to this, when the optical disc is a DVD+R, forexample, the optical disc device reports the above-described fragmentinformation to the upper device in response to a request for the trackinformation from the upper device. Also, when the optical disc is aCD-R, the optical disc device obtains the answer for a request for thetrack information from the upper device based on the track informationrecorded in the PMA as described above.

[0013] However, when the optical disc is a DVD+R, for example, asmentioned above, the fragment information is recorded in the SDCBscorresponding to the respective sessions. Thus, it is necessary for aconventional optical disc device to sequentially search the SDCBs in therespective sessions dispersed in the record area.

[0014] Accordingly, there is a problem in that the speed of responsewith respect to a track information obtaining request from the upperdevice, that is, the performance is significantly degraded.

[0015] Therefore, it is conceivable to obtain all fragment informationin advance when an optical disc is set to the drive unit. However,because of a similar reason as in the case above, a considerable amountof time is required for obtaining all fragment information. Thus, thereis a problem in that time until user access is made possible after theoptical disc is set to the drive unit, so called disc mount time, isincreased. Further, as mentioned above, the DVD+R allows up to 3056fragments to exist thereon. For this reason, considering the memorycapacity, it is difficult to store all fragment information in thememory of the drive unit.

[0016] Additionally, even in a case where designated fragmentinformation is read from the disc when the user makes a request for thefragment information, since the fragment information exists in the SCDBsof the respective sessions in a dispersed manner as mentioned above, itis necessary to sequentially search for the SCDBs having the designatedfragment. In this case, the performance with respect to the request forthe fragment information by the user is significantly degraded.

[0017] Regarding such problems, for the DVD+R, a method has beenproposed and is to be adopted as the standard where a session of whichdata recording is completed (closed session) is reported as one track tothe user even when a plurality of fragments exist in the session. Thatis, when an obtaining request for the management information includes arequest for obtaining the number of tracks, each of the closed sessionsamong the sessions included in the record area is regarded as one track(a pseudo-track) so as to calculate the number of track s in response tothe request. This is because there is no concept of the track in theDVD, the fragment in the DVD+R is for data recording, and thusindividual fragment information in the session of which data recordingis completed is not important. In other words, when recording data, awrite-once type disc such as the DVD+R requires information (fragmentinformation) of tracks existing in sessions (open sessions) of whichdata recording is not completed. However, information (fragmentinformation) of tracks in closed sessions to which data recording cannotbe further performed is not important. Thus, there is no inconvenienceif the number of the closed sessions is given as an answer to the tracknumber obtaining request.

[0018] As a result, it is not necessary to check SDCBs in all sessionswith respect to the management information obtaining request. It ispossible to immediately obtain the number of the pseudo-tracks only fromthe SCDB in the last session. Consequently, the number of tracks is, atthe maximum, 206 (=190 (the number of the pseudo-tracks)+16 (the numberof tracks in an open session)). Thus, as in the case of the CD-R, it ispossible to store information of each track in the memory of the driveunit in advance. Accordingly, a method is used in which, with respect tothe management information obtaining request by the user, managementinformation recorded in the SCDB of the last session is always reported.

[0019] However, despite such a DVD+R environment, there may still be arequest for obtaining individual fragment information in the closedsessions. For example, depending on a category where the drive unit isused, a case exists where there is a request for obtaining individualfragment information in the closed sessions so as to confirm thefragment information in data recording and the like.

[0020] In such a case, with respect to the management informationobtaining request by the user, though the session information of theprior sessions is obtained, it is impossible to obtain the fragmentinformation of the prior sessions, even if the management information isobtained from the SDCB of the last session. In other words, there is aproblem in that the user cannot obtain individual fragment informationin the closed sessions, since a means for reporting to the user thecontents of the SDCBs of desired sessions does not exist, thoughindividual fragment information in the closed sessions exists only inthe SDCBs of the corresponding sessions.

SUMMARY OF THE INVENTION

[0021] It is a general object of the present invention to provide animproved and useful information reproducing apparatus, data managementinformation obtaining method, data management information obtainingprogram, and storage medium in which the above-mentioned problems areeliminated.

[0022] It is another and more specific object of the present inventionto provide an information reproducing apparatus, data managementinformation obtaining method, data management information obtainingprogram, and storage medium that can obtain management information of adesired management information area without degrading performance, evenunder a condition where a reproducing target is an information recordingmedium on which a plurality of the management information areas exist,each of which management information areas is updated and recorded in anew area every time predetermined data recording is completed, regardingthe management information.

[0023] It is still another object of the present invention to provide aninformation reproducing apparatus, data management information obtainingmethod, data management information obtaining program, and storagemedium that can easily obtain fragment information in a desired sessionof which session data recording is completed, under a condition that areproducing target is an information recording medium conforming to thestandard of DVD+R.

[0024] It is a further object of the present invention to provide aninformation reproducing apparatus, data management information obtainingmethod, data management information obtaining program, and storagemedium that can appropriately respond to designation by a user.

[0025] In order to achieve the above-mentioned objects, according to oneaspect of the present invention, there is provided an informationreproducing apparatus reproducing information of an informationrecording medium in which a record area is divided into a plurality ofdata areas, data are recorded for each of the divided data areas,management information relating to the data recording is recorded in apredetermined management information area, and the managementinformation is updated and recorded in a new management information areaevery time predetermined data recording is completed, the informationreproducing apparatus including: a receiving part receiving, from anexternal device, an obtaining request for the management information,the obtaining request including designation of a specific managementinformation area; a management information obtaining part obtaining themanagement information relating to the data recording from the specificmanagement information area designated in the received obtainingrequest; and a reporting part reporting, to the external device, themanagement information relating to the data recording obtained from thedesignated specific management information area.

[0026] According to the above-mentioned aspect of the present invention,the information reproducing apparatus is provided with an interfacefunction that receives, from the external device, the obtaining requestfor the management information, which obtaining request includes thedesignation of the specific management information area, and obtainsmanagement information relating to data recording from the specificmanagement information area designated in the received obtainingrequest. Thus, it is possible to obtain, without degrading performance,management information of the management information area that a userdesires, even under a condition that a reproducing target is aninformation recording medium on which a plurality of the managementinformation areas exist, and the management information area is updatedand recorded in a new area every time predetermined data recording iscompleted with respect to the management information.

[0027] Also, the record area may include at least one session thatincludes a plurality of tracks as the data areas. In addition, themanagement information relating to the data recording, which managementinformation is recorded in each of the management information areas, mayinclude all track information in a session and all session informationof sessions before the session.

[0028] Accordingly, it is possible to easily obtain the trackinformation of a session by requesting for obtaining the managementinformation with the designation of a desired management informationarea that belongs to the session of which track information is needed.

[0029] In addition, the information recording medium may be aninformation recording medium that conforms to the standard of DVD+R.Also, each of the management information areas may be a SDCB, and thetrack may be a fragment.

[0030] Accordingly, specifically, under a condition that the informationrecording medium that conforms to the standard of DVD+R is a reproducingtarget, it is possible to easily obtain, from the corresponding SDCB,fragment information in a desired session of which data recording isalready completed.

[0031] Further, in the information reproducing apparatus according tothe present invention, the reporting part may report, to the externaldevice, the newest management information relating to data recordingobtained from the designated specific management information area.

[0032] Accordingly, among the management information obtained from thespecific management information area designated by the user via theexternal device, it is possible to report the newest managementinformation that is added and updated.

[0033] Additionally, the information reproducing apparatus according tothe present invention may further include a determining part determiningwhether or not the designated specific management information areaexists on the information recording medium, wherein the reporting partmakes an error report to the external device when the designatedspecific management information area does not exist.

[0034] Accordingly, when the management information area designated bythe user via the external device does not exist on the informationrecording medium, since it is highly possible that an erroneousdesignation operation of management information area is performed, anerror report is made. Thus, it is possible to avoid reporting, to theuser, management information according to an erroneous managementinformation area.

[0035] In addition, the information reproducing apparatus according tothe present invention may further include a determining part determiningwhether or not the designated specific management information areaexists on the information recording medium, wherein the reporting partreports, to the external device, management information relating to thedata recording obtained from a last management information area when thedesignated specific management information area does not exist.

[0036] Accordingly, when the management information area designated bythe user via the external device does not exist on the informationrecording medium, an error report is not made, but managementinformation of the last management information area is reported. Hence,it is possible for the user to obtain the management information of thelast management information area without bothering himself/herself aboutthe number of the management information areas existing on theinformation recording medium.

[0037] Furthermore, the information reproducing apparatus according tothe present invention may further include a default value determiningpart determining whether or not the designated specific managementinformation area corresponds to a specific default value, the specificdefault value being set in advance with respect to designation of thespecific management information area, wherein the reporting partreports, to the external device, management information relating to thedata recording obtained from a last management information area when thedesignated specific management information area is the default value.

[0038] Accordingly, when the management information area is notspecifically designated but is the default value, the managementinformation obtained from the last management information area isreported. Hence, it is possible to maintain the compatibility with amethod that always obtains the management information from the lastmanagement information area.

[0039] Additionally, according to another aspect of the presentinvention, there is provided a data management information obtainingmethod for an. information recording medium in which a record area isdivided into a plurality of data areas, data are recorded for each ofthe divided data areas, management information relating to the datarecording is recorded in a predetermined management information area,and the management information is updated and recorded in a newmanagement information area every time predetermined data recording iscompleted, the data management information obtaining method includingthe steps of: receiving, from an external device, an obtaining requestfor management information, the obtaining request including designationof a specific management information area; obtaining managementinformation relating to data recording from the specific managementinformation area designated in the received obtaining request; andreporting, to the external device, the management information relatingto the data recording obtained from the designated specific managementinformation area.

[0040] Accordingly, the information reproducing apparatus is providedwith an interface function that receives, from the external device, theobtaining request for the management information, which obtainingrequest includes the designation of the specific management informationarea, and obtains management information relating to data recording fromthe specific management information area designated in the receivedobtaining request. Thus, it is possible to obtain, without degradingperformance, management information of the management information areathat a user desires, even under a condition that a reproducing target isan information recording medium on which a plurality of the managementinformation areas exist, and the management information area is updatedand recorded in a new area every time predetermined data recording iscompleted with respect to the management information.

[0041] Also, the data management information obtaining method mayfurther include the step of: determining whether or not the designatedspecific management information area exists on the information recordingmedium, wherein the step of reporting makes an error report to theexternal device when the designated specific management information areadoes not exist.

[0042] Accordingly, when the management information area designated bythe user via the external device does not exist on the informationrecording medium, since it is highly possible that an erroneousdesignation operation of management information area is performed, anerror report is made. Thus, it is possible to avoid reporting, to theuser, management information according to an erroneous managementinformation area.

[0043] In addition, the data management information obtaining methodaccording to the present invention may further include the step of:determining whether or not the designated specific managementinformation area exists on the information recording medium, wherein thestep of reporting reports, to the external device, managementinformation relating to the data recording obtained from the lastmanagement information area when the designated specific managementinformation area does not exist.

[0044] Accordingly, when the management information area designated bythe user via the external device does not exist on the informationrecording medium, an error report is not made, but managementinformation of the last management information area is reported. Hence,it is possible for the user to obtain the management information of thelast management information area without bothering himself/herself aboutthe number of the management information areas existing on theinformation recording medium.

[0045] The data management information obtaining method according to thepresent invention may further include the step of: determining whetheror not the designated specific management information area correspondsto a specific default value, the specific default value being set inadvance with respect to the designation of the specific managementinformation area, wherein the step of reporting reports, to the externaldevice, management information relating to the data recording obtainedfrom the last management information area when the designated specificmanagement information area is the specific default value.

[0046] Accordingly, when the management information area is notspecifically designated but is the default value, the managementinformation obtained from the last management information area isreported. Hence, it is possible to maintain the compatibility with amethod that always obtains the management information from the lastmanagement information area.

[0047] Additionally, according to another aspect of the presentinvention, there is provided a data management information obtainingprogram installed in a computer of an information reproducing apparatusreproducing information of an information recording medium in which arecord area is divided into a plurality of data areas, data are recordedfor each of the divided data areas, management information relating, tothe data recording is recorded in a predetermined management informationarea, and the management information is updated and recorded in a newmanagement information area every time a predetermined data recording iscompleted, the data management information obtaining program causing thecomputer to carry out a data management information obtaining processincluding the instructions of: causing the computer to receive, from anexternal device, an obtaining request for management information, theobtaining request including designation of a specific managementinformation area; causing the computer to obtain management informationrelating to data recording from the specific management information areadesignated in the received obtaining request; and causing the computerto report, to the external device, the management information relatingto the data recording obtained from the designated,specific managementinformation area.

[0048] Accordingly, the data management information obtaining programcauses the computer to carry out an interface function that receives,from the external device, the obtaining request for the managementinformation, which obtaining request includes the designation of thespecific management information area, and obtains management informationrelating to data recording from the specific management information areadesignated in the received obtaining request. Thus, it is possible toobtain, without degrading performance, management information of themanagement information area that a user desires, even under a conditionthat a reproducing target is an information recording medium on which aplurality of the management information areas exist, and the managementinformation area is updated and recorded in a new area every timepredetermined data recording is completed with respect to the managementinformation.

[0049] The data management information obtaining program according tothe present invention may further include the instruction of: causingthe computer to determine whether or not the designated specificmanagement information area exists on the information recording medium,wherein the instruction of causing the computer to report causes thecomputer to carry out a process of making an error report to theexternal device when the designated specific management information areadoes not exist.

[0050] Accordingly, when the management information area designated bythe user via the external device does not exist on the informationrecording medium, since it is highly possible that an erroneousdesignation operation of management information area is performed, anerror report is made. Thus, it is possible to avoid reporting, to theuser, management information according to an erroneous managementinformation area.

[0051] In addition, the data management information obtaining programaccording to the present invention may further include the instructionof: causing the computer to determine whether or not the designatedspecific management information area exists on the information recordingmedium, wherein the instruction of causing the computer to report causesthe computer to perform a process of reporting, to the external device,management information relating to data recording obtained from the lastmanagement information area when the designated specific managementinformation area does not exist.

[0052] Accordingly, when the management information area designated bythe user via the external device does not exist on the informationrecording medium, an error report is not made, but managementinformation of the last management information area is reported. Hence,it is impossible for the user to obtain the management information ofthe last management information area without bothering himself/herselfabout the number of the management information areas existing on theinformation recording medium.

[0053] Further, the data management information obtaining programaccording to the present invention may further include the instructionof: determining whether or not the designated specific managementinformation area corresponds to a specific default value, said specificdefault value being set in advance with respect to the designation ofthe specific management information area, wherein the instruction ofcausing the computer to report causes the computer to report, to theexternal device, management information relating to data recordingobtained from the last management information area when the designatedspecific management information area is the specific default value.

[0054] Accordingly, when the management information area is notspecifically designated but is the default value, the managementinformation obtained from the last management information area isreported. Hence, it is possible to maintain the compatibility with amethod that always obtains the management information from the lastmanagement information area.

[0055] Additionally, according to another aspect of the presentinvention, there is provided a computer-readable storage medium storingthe data management information obtaining program as described above.

[0056] Accordingly, it is possible to obtain similar effects obtainedfrom the data management information obtaining program.

[0057] Other objects, features and advantages of the present inventionwill become more apparent from the following detailed description whenread in conjunction with the following drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0058]FIG. 1 is a block diagram showing a general structure of anoptical disc device according to one embodiment of the presentinvention;

[0059]FIG. 2 is a schematic diagram showing an example of amulti-session format of a DVD+R;

[0060]FIG. 3 is a table showing an example of the format of a SDCB;

[0061]FIG. 4 is a table showing an example of the format of “FragmentItem”;

[0062]FIG. 5 is a table showing an example of the format of “PreviousSession Item”; and

[0063]FIG. 6 is a flow chart generally showing an example of amanagement information obtaining process.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0064] A description will be given of one embodiment of the presentinvention, with reference to the drawings. FIG. 1 is a block diagramshowing the general structure of an optical disc device 1 as aninformation reproducing apparatus according to the embodiment.

[0065] The optical disc device 1 is constructed by a spindle motor 3 fordriving an optical disc 2 as an information recording medium to rotate,an optical pickup unit 4, a laser control circuit 5, a motor driver 6, areproduction signal processing circuit 7, a servo controller 8, a bufferRAM 9, a buffer manager 10, an interface 11, a ROM 12, a CPU 13, a RAM14 and the like. It should be noted that arrows in FIG. 1 do notindicate all connections among the blocks, but indicate typical flows ofsignals and information.

[0066] More specifically, first, as the optical disc 2, an informationrecording medium conforming to the standard of the DVD+R (hereinaftersimply referred to as a “DVD+R”) is targeted.

[0067] The optical pickup unit 4 is constructed by including asemiconductor laser as a light source, an optical system that guides alaser beam emitted from the semiconductor laser to a storage surface ofthe optical disc 2 and includes an objective lens and the like guidingthe returning beam reflected by the recording surface to a predeterminedreceiving position, a receiver arranged at the receiving position andreceiving the returning beam, driving systems (focusing actuator,tracking actuator, seek motor and the like)(none of them are shown), andthe like. The receiver outputs, to the reproduction signal processingcircuit 7, a current (electric current signal) according to the amountof light received.

[0068] The servo controller 8 generates a control signal controlling thefocusing actuator of the optical pickup unit 4 based on a focus errorsignal, and generates a control signal controlling the tracking actuatorof the optical pickup unit 4 based on a track error signal. Thesecontrol signals are output to the motor driver 6 from the servocontroller 8.

[0069] The motor driver 6 drives, based on the control signals from theservo controller 8, the focusing actuator and tracking actuator of theoptical pickup unit 4. In addition, based on an instruction from the CPU13, the motor driver 6 controls the spindle motor 3 so that the linearvelocity of the optical disc 2 becomes constant. Further, based on aninstruction from the CPU 13, the motor driver 6 drives the seek motorfor the optical pickup unit 4 so as to radially move the optical pickupunit 4 toward a target track of the optical disc 2.

[0070] The interface 11 is a two-way communication interface with a host(for example, a PC), which is an external device. The interface 11conforms to the standard interfaces of ATAPI, SCSI, and the like.

[0071] The CPU 13 constitutes, with the ROM 12 and the RAM 14, amicrocomputer (computer) that the optical disc device 1 includes. TheROM 12 that also functions as a storage medium stores a programincluding a data management information obtaining program, as describedlater, written in a code decodable by the CPU 13. The CPU 13 controlsthe operation of each of the above-described parts according to theprogram stored in the ROM 12, and temporarily stores such data asnecessary for the control in the RAM 14. It should be noted that theprogram stored in the ROM 12 is loaded (installed) to a main memory (notshown) of the CPU 13 when the power of the optical disc device 1 isturned ON.

[0072] Next, a description will be given of an example of amulti-session format of the DVD+R constituting the optical disc 2 thatis the target of this embodiment, by referring to a schematic diagram ofFIG. 2. It should be noted that the file system of the optical disc 2conforms to the sequential UDF standard.

[0073] In the example shown in FIG. 2, for ease of explanation, a caseis shown where two closed sessions, Sessions 1 and 2 of which datarecording is completed, and one open session, Session 3 of which datarecording is started but not completed exist on the optical disc 2, forexample. Each of the Sessions 1, 2 and 3 includes three fragments (ninefragments indicated by Frag. No. 1 through 9). For each of the Sessions1, 2 and 3, every time data recording of each session is completed, theSDCB (session disc control block) constituting a management informationarea is secured in a predetermined area, for example; a lead-in (or anintro), and management information relating to the data recording isrecorded.

[0074]FIG. 3 shows an example of such a SDCB format. As shown in FIG. 3,the SDCB includes descriptions of “Contents Descriptor”, “UnknownContents Descriptor Actions”, “Drive ID”, “Session Number” and the like.Further, as information specific to the SDCB, the SDCB includes aplurality of (0 through N) “Session Items”, each being constructed by 16bytes.

[0075] Such “Session Item” includes two kinds: Fragment Item indicatingfragment information in the session; and Previous Session Itemindicating session information of the sessions before this session.

[0076]FIG. 4 shows an example of the format of the “Fragment Item”. Theformat of the “Fragment Item” is set such that the fragment informationof “Fragment number”, “Fragment start address”, “Fragment end address”and the like is written as the management information. Such “FragmentItem” is prepared, as one of the “Session Items”, for each fragmentexisting in the session. In the example shown in FIG. 2, three “FragmentItems” exist for each of the SDCBs.

[0077]FIG. 5 shows an example of the format of the “Previous SessionItem”. The format of the “Previous Session Item” is set such thatsession information of “Previous session number”, “Previous sessionstart address”, “Previous session end address” and the like are writtenas the management information. Such “Previous Session Item” is prepared,as one of the “Session Items”, for each session existing before thesession.

[0078] Each of the SDCBs includes a recordable area. The information ofthe SDCB is added in a similar manner when a track or a session isadded, for example.

[0079] Returning to FIG. 2, in the multi-session format as shown in FIG.2, with respect to the closed sessions as indicated by the Sessions 1and 2, the optical disc device 1 is set so as to make a report, to thehost, by regarding each of the sessions as one track, even if aplurality of tracks (fragments) exist in the session. Accordingly, asshown in FIG. 2, the track numbers of the closed sessions are equal tothe session numbers. On the other hand, with respect to,the open sessionas indicated by the Session 3, the number of fragments matches thenumber of tracks. That is, the track number of the first track of theopen session is the session number, and the track numbers thereafter areincremented one by one. In the example shown in FIG. 2, the fragmentnumbers 1 through 3 are regarded as the track number 1, the fragmentnumbers 4 through 6 are regarded as the track number 2, and the fragmentnumbers 7, 8 and 9 are regarded as the track numbers 3, 4 and 5,respectively.

[0080] Thus, under such a condition, it is possible to immediatelyobtain the fragment information in the session 3 and the number oftracks in the record area, by obtaining and reporting the managementinformation that is written in the last SDCB included in the Session 3,which is the last session, with respect to the management informationobtaining request from the host side. Therefore, setting is made suchthat the last SDCB included in the last session becomes the target ofthe management information obtaining request from the host side.

[0081] Under such a condition, with respect to the previous sessions,only the session information is obtained and the fragment informationcannot be obtained. In other words, there is a problem in that the usercannot obtain individual fragment information in the closed sessions,since a means for reporting, to the host, the contents of the SDCB of adesired session does not exist, though individual fragment informationin the closed sessions exists only in the SDCB of the correspondingsession. In the example shown in FIG. 2, it is impossible to obtain thefragment information with respect to the fragment numbers 1 through 6.

[0082] Thus, in this embodiment, an interface is added that can provideaccess to the SDCB of a desired session and obtain the fragmentinformation in the session so that even the management information ofpast SDCBs can be arbitrarily reported.

[0083] A description will be given of an example of control of a datamanagement information obtaining process carried out by the CPU 13 inthe optical disc device 1 according to this embodiment, with referenceto the flow chart shown in FIG. 6. In this embodiment, in order to addthe above-described interface, it is assumed that the host sidedesignates the session number so as to specify a desired SDCB whenmaking an obtaining request for the management information. Whenspecifying the SDCB by designating the session number, it is possible tospecify the last SDCB belonging to the last session by inputting thesession number thereof. However, it is assumed that a field fordesignating the session number is normally set to a default setting (inthis embodiment, a session number “0”, which does not exist on theoptical disc 2, is set) so that the last SDCB can be designated withoutspecifically designating the session number.

[0084] Additionally, in the optical disc device 1, when the optical disc2 is mounted to a predetermined position of the optical disc device 1,the CPU 13 obtains information relating to the closed session recordedon a predetermined position in the record area of the optical disc 2,extracts the address of the last closed session based on theinformation, and checks whether or not an open session exists followingthe closed session. When an open session exists, the record contents ofthe SDCB of the open session are read and copied to the RAM 14. When anopen session does not exist, the record contents of the SDCB of the lastclosed session are read and copied to the RAM 14. In other words, it isassumed that prior to the process of this embodiment, which is to beexplained by using FIG. 6, the management information of the last SDCBis already copied to the RAM 14. In the example of FIG. 2, themanagement information written in the last SDCB included in the Session3 is copied to the RAM 14.

[0085] First, when there is a request for obtaining managementinformation with the designation of the session number from the hostside, the designated session number is obtained in step S1. When thedesignated session number is obtained, it is determined whether or notthe session of the session number exists on the optical disc 2 in stepS2. The determination is made based on the limitation that the number ofsessions that can exist on the optical disc 2 is up to 191 sessions in acase of a DVD+R, and by referring to the session information obtainedfrom the last SDCB and already stored in the RAM 14.

[0086] When the session of the designated session number exists on theoptical disc 2 (YES in step S2), the management information as shown inFIGS. 3 through 5 recorded in the SDCB belonging to the session of thedesignated session number is read from the optical disc 2 in step S3. Asaccess control to the SDCB in this case, for example, referring to themanagement information of the last SDCB already stored in the RAM 14,the session start address of the designated session may be read, and theSDCB of the target session may be searched based on the address. Byreading the SDCB, it is possible to obtain the management informationsuch as the number of each fragment existing in the session, and thefragment information such as the address and the like. For instance, inthe example shown in FIG. 2, when the Session 2 is designated, it ispossible to obtain, from the SDCB belonging to the Session 2, thefragment information relating to the fragments 4, 5 and 6 in the Session2.

[0087] Thereafter, in step S4, the management information including thefragment information obtained from the SDCB of the designated session isreported to the host side (user), and the management informationobtaining process ends. The contents of the management informationreported to the host side are the newest management information in thesession of the session number that is designated by the user. Forexample, when there is a session deletion or the like before the sessiondesignated by the user, management information including the deletioninformation is reported.

[0088] On the other hand, when the session of the designated sessionnumber does not exist on the optical disc 2 (NO in step S2), in step S5,it is determined whether or not the session number is a default valuewith respect to the session number designation of the optical discdevice 1. This is because, in this embodiment, the default value withrespect to the session number designation is set to the session number0.

[0089] As a result of the determination, when the session number is notthe default value but the session number does not exist on the opticaldisc 2 (NO in step S5), no particular process is performed, and an errorreport is made to the host side via the interface 11 in step S6.

[0090] Accordingly, when the session number designated by the user viathe host does not exist on the optical disc 2, it is highly possiblethat an erroneous session number designation operation is made. Thus, bymaking an error report, it is possible to avoid reporting, to the user,the management information of an erroneous SDCB.

[0091] In addition, when the designated session number is the defaultvalue (YES in step 55), the management information including thefragment information obtained from the last SDCB is reported to the hostside via the interface 11 in step S7, and the management informationobtaining process ends. Since the management information obtained fromthe last SDCB is already stored in the RAM 14, the report in this caseis made by reading the management information from the RAM 14.

[0092] That is, as mentioned above, when a method is employed where themanagement information is always obtained from the last SDCB, the usermakes the management information obtaining request without designatingthe session number. Even in a method where the designation of thesession number is required as in this embodiment, the field fordesignating the session number is set to the session number 0 as thedefault setting so that input of a specific number is not required evenwhen the last SDCB is to be designated. However, when the error report(step S6) is made on the grounds that the session number 0 does notexist on the optical disc 2, compatibility with the method where themanagement information is always obtained from the last SDCB is lacking.Thus, the last session number to which the last SDCB belongs must bedesignated. In that respect, it is possible to maintain compatibilitywith the method where the management information is always obtained fromthe last SDCB by reporting the management information obtained from thelast SDCB when the session number is not specifically designated but thedefault value is set.

[0093] Further, when the designated session number does not exist on theoptical disc 2 (NO in step S2), as indicated by a two-dot chain line inFIG. 6, without making the error report (step S6) whether the sessionnumber is the default value or not, the management information includingthe fragment information obtained from the last SDCB may be reported tothe host side via the interface 11 (step S7), and the managementinformation obtaining process may be ended. Since the managementinformation obtained from the last SDCB is already stored in the RAM 14,the report in this case is performed by reading the managementinformation from the RAM 14.

[0094] In other words, it is possible for the user to obtain themanagement information of the last SDCB without botheringhimself/herself about the number of sessions existing on the opticaldisc 2, when the session number that is designated by the user via thehost does not exist on the optical disc 2. For example, in the DVD+R asin this embodiment, up to 191 sessions can exist. However, when asession number larger than this is designated intentionally, it ispossible to obtain the management information of the last SDCB,irrespective of the number of sessions existing on the optical disc 2.Accordingly, it is possible to correspond to a case where the defaultvalue for obtaining the management information of the last SDCB is notset.

[0095] Further, in this embodiment, the description has been given forthe case where the optical disc 2 is a DVD+R. However, the presentinvention may be applied to information recording media on which datarecording is made by dividing the record area into a plurality of dataareas such as sessions and tracks, management information relating tothe data recording is recorded in predetermined management informationareas, and the management information is updated and recorded to a newmanagement information area every time predetermined data recording iscompleted.

[0096] Also, the optical disc device 1 of this embodiment may be aso-called built-in type, which is arranged in the same housing as thatof the host, or a so-called external type, which is arranged in ahousing different from that of the host.

[0097] Furthermore, the description has been given of the case where theoptical disc device is used as the information reproducing apparatus.However, information reproducing apparatuses capable of usinginformation recording media on which data recording is made by dividingthe record area into a plurality of data areas such as sessions andtracks, management information relating to the data recording isrecorded in predetermined management information areas, and themanagement information is updated and further recorded to a newmanagement information area every time a predetermined data recording iscompleted may be used. Of course, information recording/reproducingapparatuses having a recording function as well as a reproducingfunction may be used.

[0098] The present invention is not limited to the specificallydisclosed embodiments, and variations and modifications may be madewithout departing from the scope of the present invention.

[0099] The present application is based on Japanese priority applicationNo. 2002-005824 filed on Jan, 15, 2002, the entire contents of which arehereby incorporated by reference.

What is claimed is:
 1. An information reproducing apparatus reproducinginformation of an information recording medium in which a record area isdivided into a plurality of data areas, data are recorded for each ofthe divided data areas, management information relating to the datarecording is recorded in a predetermined management information area,and the management information is updated and recorded in a newmanagement information area every a time predetermined data recording iscompleted, said information reproducing apparatus comprising: areceiving part receiving, from an external device, an obtaining requestfor the management information, said obtaining request includingdesignation of a specific management information area; a managementinformation obtaining part obtaining the management information relatingto the data recording from the specific management information areadesignated in the received obtaining request; and a reporting partreporting, to the external device, the management information relatingto the data recording obtained from the designated specific managementinformation area.
 2. The information reproducing apparatus as claimed inclaim 1, wherein the record area includes at least one session having aplurality of tracks as the data areas, and the management informationrelating to the data recording recorded in each of the managementinformation areas includes all track information of the session and allsession information of sessions recorded before the session.
 3. Theinformation reproducing apparatus as claimed in claim 2, wherein theinformation recording medium conforms to a standard which is the DVD+Rstandard, each of the management information areas is a session disccontrol block, and each of the tracks is a fragment.
 4. The informationreproducing apparatus as claimed in claim 1, wherein the reporting partreports, to the external device, newest management information relatingto the data recording obtained from the designated specific managementinformation area.
 5. The information reproducing apparatus as claimed inclaim 1, further comprising: a determining part determining whether ornot the designated specific management information area exists on theinformation recording medium, wherein, the reporting part makes an errorreport to the external device when the designated specific managementinformation area does not exist.
 6. The information reproducingapparatus as claimed in claim 1, further comprising: a determining partdetermining whether or not the designated specific managementinformation area exists on the information recording medium, wherein thereporting part reports, to the external device, the managementinformation relating to the data recording obtained from a lastmanagement information area when the designated specific managementinformation area does not exist.
 7. The information reproducingapparatus as claimed in claim 1, further comprising: a default valuedetermining part determining whether or not the designated specificmanagement information area corresponds to a specific default value,said specific default value being set in advance with respect to thedesignation of the specific management information area, wherein thereporting part reports, to the external device, the managementinformation relating to the data recording obtained from a lastmanagement information area when the designated specific managementinformation area is the specific default value.
 8. A data managementinformation obtaining method for an information recording medium inwhich a record area is divided into a plurality of data areas, data arerecorded for each of the divided data areas, management informationrelating to the data recording is recorded in a predetermined managementinformation area, and the management information is updated and recordedin a new management information area every time a predetermined datarecording is completed, said data management information obtainingmethod comprising the steps of: receiving, from an external device, anobtaining request for the management information, said obtaining requestincluding designation of a specific management information area;obtaining the management information relating to the data recording fromthe specific management information area designated in the receivedobtaining request; and reporting, to the external device, the managementinformation relating to the data recording obtained from the designatedspecific management information area.
 9. The data management informationobtaining method as claimed in claim 8, further comprising the step of:determining whether or not the designated specific managementinformation area exists on the information recording medium, wherein thestep of reporting the management information makes an error report tothe external device when the designated specific management informationarea does not exist.
 10. The data management information obtainingmethod as claimed in claim 8, further comprising the step of:determining whether or not the designated specific managementinformation area exists on the information recording medium, wherein thestep of reporting the management information reports, to the externaldevice, the management information relating to the data recordingobtained from a last management information area when the designatedspecific management information area does not exist.
 11. The datamanagement information obtaining method as claimed in claim 8, furthercomprising the step of: determining whether or not the designatedspecific management information area corresponds to a specific defaultvalue, said specific default value being set in advance with respect tothe designation of the specific management information area, wherein,when the designated specific management information area is the specificdefault value, the step of reporting the management information reports,to the external device, the management information relating to the datarecording obtained from a last management information area.
 12. A datamanagement information obtaining program installed in a computer of aninformation reproducing apparatus reproducing information of aninformation recording medium in which a record area is divided into aplurality of data areas, data is recorded for each of the divided dataareas, management information relating to the data recording is recordedin a predetermined management information area, and the managementinformation is updated and recorded in a new management information areaevery time predetermined data recording is completed, said datamanagement information obtaining program for causing the computer tocarry out a management information obtaining process comprising theinstructions of: causing the computer to receive, from an externaldevice, an obtaining request for management information, said obtainingrequest including designation of a specific management information area;causing the computer to obtain the management information relating tothe data recording from the specific management information areadesignated in the received obtaining request; and causing the computerto report, to the external device, the management information relatingto the data recording obtained from the designated specific managementinformation area.
 13. The data management information obtaining programas claimed in claim 12, further comprising the instruction of: causingthe computer to determine whether or not the designated specificmanagement information area exists on the information recording medium,wherein the instruction of causing the computer to report the managementinformation causes the computer to carry out a process of making anerror report to the external device when the designated specificmanagement information area does not exist.
 14. The data managementinformation obtaining program as claimed in claim 12, further comprisingthe instruction of: causing the computer to determine whether or not thedesignated specific management information area exists on theinformation recording medium, wherein the instruction of causing thecomputer to report the management information causes the computer toperform a process of reporting, to the external device, the managementinformation relating to the data recording obtained from a lastmanagement information area when the designated specific managementinformation area does not exist.
 15. The data management informationobtaining program as claimed in claim 12, further comprising theinstruction of: causing the computer to determine whether or not thedesignated specific management information area corresponds to aspecific default value, said specific default value being set in advancewith respect to the designation of the specific management informationarea, wherein the instruction of causing the computer to report themanagement information causes the computer,to report, to the externaldevice, the management information relating to the data recordingobtained from a last management information area when the designatedspecific management information area is the specific default value. 16.A computer-readable storage medium storing a data management informationobtaining program, said data management information obtaining programbeing installed to a computer of an information reproducing apparatusreproducing information of an information recording medium in which arecord area is divided into a plurality of data areas, data are recordedfor each of the divided data areas, management information relating tothe data recording is recorded in a predetermined management informationarea, and the management information is updated and recorded in a newmanagement information area every time a predetermined data recording iscompleted, and said data management information obtaining program forcausing the computer to carry out a data management informationobtaining process comprising the instructions of: causing the computerto receive, from an external device, an obtaining request for managementinformation, said obtaining request including designation of a specificmanagement information area; causing the computer to obtain themanagement information relating to the data recording from the specificmanagement information area designated in the received obtainingrequest; and causing the computer to report, to the external device, themanagement information relating to the data recording obtained from thedesignated specific management information area.